A block can have way more --or less -- than 2,000 transactions depending on the block weight of the individual transactions.
This goes back to the Topic Question,
How to handle more than 2k plus number of transactions in 10 minutes?
See, if we go back to December when there were more than 2000 transactions happening approximately every 10 minutes, today's smooth-flowing mempool could get clogged again.
I'm curious too if they are working for some solutions in case of another micro-transactions rush. Since LN is currently unavailable for the mainstream 3rd party client users.
Is SegWit enough to fit more transactions in a block?
Even during that time, we saw only a few Blocks being filled to 2MB, so most blocks was not filled to capacity back then. SegWit also made spamming more expensive. The scenario has changed a bit since then, because SegWit adoption has grown and I think Coinbase's adoption of SegWit will also help.
A lot of the other exchanges has also implemented "Batching" & "SegWit", which will help, when we have a repeat of those kinds of volumes.